Furnace



w. M. DUNCAN FURNACE Filed Feb.

Nov. 30 1926.

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Nov. 30 1926. 1,608,728

W. M. DUNCAN FURNACE Filed Feb. 1. 1922 5 sheets-sheet s /12 Venfar:

MM //fifm e il Patented Nov. 30, 1926.

STATES WLLIAM M. DUNCAN, 0F ALTON, ILLINOIS.

FURNACE.

Application led February 1, 1922. Serial No. 533,471.

This invention relates to improvements in furnaces, and more particularly to a furnace provided with draft boxes surrounded by traveling grate, the main object being to provide a simple means for removing ashes from the draft boxes which lie below the fuel-supporting portion of the grate.

ln the preferred form of the invention, each draft box is open at the top for the discharge of draft through the fuel-supporting portion of the grate, and this allows the ashes, together with the fine particles of fuel, to drop into the draft boa. As a means for removing the ashes from the draft boa, l preferably provide said draft boa with an inclined bottom portion having an opening for the egress of ashes, said opening being normally closed by a closure which may be opened by certain mechanism, the operating portion of which entends outside of the furnace, whereby said ashes are per mitted to fall by gravity to the lower course of the traveling grate through which they pass.

lanother object is to provide an ash discharge means adapted to be carried by a portable mechanical stolrer, having detachable elements allowing the. portable stolier to be moved into and out of the furnace.

Fig. l is a longitudinal section, illustrating a mechanical stolrer embodying the features of this invention, the middle portion of the apparatus being broken away.

F ig. ll is a transverse section on the line Il-H, of Fig. l.

Fig. Hl is an enlarged fragmentary section showing the lower portion of a draft box, the closure being shown in place closing the opening therein, and a portion of the mechanism for retaining said closure in such position being shown.

Fig. lV is a fragmentary view showing the sealing strip for preventing leakage of draft around the closure when saidv closure is in place closing the ash outlet.

Fig. V is a fragmentary section showing a modified form of the invention wherein the ash opening, instead of being` at an angle to the top edge of the draft box, as in the preferred construction, parallel there-A with. Y

To illustrate the invention, `lhave sho-wn a mechanical Stoker comprising; an endless chain grate. A supported between Vside frame members 1 meunted on wheels 2. The chain erste @surprises mehr erste little @meer ed by means of pivot rods a arranged transversely of the grate. A power shaft 5 (if l), supported by the side frames 1, is lprovided with any desired number of sprocket wheels 6 for transmitting` movement to the endless chain grate. The chain grate passes around the .sprocket wheels G and also around a plain idle wheel, or roll 7, the latter being mounted on a shaft The fuel passes from a hopper 9 to the top face of the grate, as indicated by arrows in Fig. l.

The furnace is provided with suitable side walls B and B', including refractory mem bers 10 located adjacent to the side margins of the grate. The lower portion of the side wall B is hollow, as shown in Fig. Il, to provide an inlet passageway 11 for the draft. 12 designates draft bones surrounded by the traveling grate and extending from one side frame 1 at one side of the grate to the side frame 1 at the other Side thereof. fill of these box-es are open at the top to provide for the 'delivery of the draft to the grate, and are provided with vertical side walls in the form of flanged beams.

One end of ch draft box is provided with an intake nipple 13 for the admission of draft. Since the grate is supported by a portable frame, including the side frame members 1 adapted to be moved into and out of the furnace, the nipples 13 are detachable, each nipple being telescoped with one of the side frame members l and also with one of the furnace walls.

Each draft box 12 is provided with an inclined bottom, said inclined bottom being produced by a` V-shaped bottom member 14 which is secured, at its upper edges, to the opposite side members of said dr rft box. Formed in each of the V-shaped bottom members 14 is an ash discharge opening 15, extending longitudinally of said draft box, said ash discharge opening terminating just short of the side frame members 1. lt will be noted by referring to Fig. l of the draw ing that a portion of the ash discharge opening 15 is located at the lowermost point of the inclined bottoni of each draft box, and asaresult thereof all of the ashes, and every small particle of fuel which drops into a draft box, will be conveyed bythe inclined bottom-walls of said draft'boi; to said ash 'discharge opening.

Extending longitudinally of each draf-tbox'llis a shaft 1.6 rockablysupported in betises .17 sans @frei-.lesive portions of the l-shaped bottom 14. One end portion of said shaft entends through one of the side frame members 1 and is provided with a non-circular end adapted to receive a suitable coupling which connects said shaft 16 to operating mechanism which will be hereinafter set forth.

Mounted on each of the shafts 16, and adapted to swing independently thereof, is a closure 18, adapted to close the ash discharge opening` in the draft box 12. Each of said closures preferably comprises a casting overlappingY the margins of the opening 15 and being provided with a plurality of lugs 19, each of which is provided with a. yoled end adapted to embrace the shaft 16. To prevent the lugs 19 from being displaced from the shaft 16, a bolt 20 is passed through the projecting legs 19 of said lugs (Fig. HI).

, Since the successful operation of a furnace of the class described herein depends upon eflicient means for controlling the flow of air to or from the endless chain grate, it is im'- portant to close the draft boxes in such a manner that the draft will not be materially affected by leakage, heno-e a tight joint is necessary between the closures 18 and those portions of the draft boxes adjacent to the ash discharge openings 15. A tight joint between the parts mentioned could be obtained by carefully machining the meeting faces of said parts, but this is a rather expensive operation and much of it is dispensed with by th-e use of parts which will now be described.

Secured to one of the inclined portions of each of the V-shaped bottom members 14 is an adjustable sealing plate 21, said sealing` plate being provided with a plurality of elongated slots 22, each of which is adapted to receive a bolt 3 which passes through an opening in said inclined wall of the V-shaped bottoni and through said elongated slot, whereby said sealing plate is adjustably held in place. To adjust the sealing plate relative to said i! -shaped bottom, it is apparent that it is only necessary to loosen the bolt 23, after which said sealing plate may be moved freely toward or away from the closure 18 to locate said sealing plate in the desired position, where it may be fixed b y again tight ening said bolt 23. The particular advantage of using the sealing plate 21, aside from its adjustability, lies in the fact that to obtain a tight j oint between the closure and the V-shaped bottom of the draft box it is only necessary to machine the lower edge of the comparatively narrow plate 21, and that narrow portion of the closure which contacts with said sealing plate, while if said plate were not used all of the meeting faces of said closure and said V-sh aped bottom wouldY have to Vbe machined. K The adjustability of the sealing plate, of course, permits manipula# passageway.

neoefree tions of the dogs 2a contact Vwith said closure it points which, are approximately midway between the upper and lower edges of said closure. l-lence, if the shaft 1G Vwere rocked in a direction to force the closure contacting portions of the dogs aga-inst the closure, said closure would be forced. tightly against the `if-shaped bottom of the draft box, and because the pressure is apyplied directly against said closure at points equidistant from tho upper and lower edges of the closure, said pressure. will be equally distributed along said edges of said closure and a tight joint will result.

Each. of the shafts 1G is provided at one of its enas with a non-circular portion 16, which is adapted to receive a coupling having` a non-circular opening for the ieception of said non-circular end, the end of said coupling opposite to the end that en gages the shaft 1G beingl secured by means of a: bolt to an operating shaft 26. The shaft 26, as will be observed by referring to Fig. ll of the drawing, extends across the inlet passageway ll and through the portions of the furnace wall B on either side `of said y imbedded in the outer portion of the furnace wall B, at the point where the operating shaft 26 extends through said wall portion, is a hollow casting 2T having a reduced portion 2T on its inner face, the purpose of which will be sub sequently pointed out.

Supported by the lower portion of each hollow casting 27 is a bearing 28,' in which one of the operating shafts 26 is journaled, said bearing being secured to said hollow casting by means of suitable bolts lor other fastening means, and is provided with a rigid toothed segment 29. .am operating lever 30 is liXed to the outer endl of each operating shaft 26, said lever being provided with a pivoted pawl S1 which engages the toothed facevof the segment 29. From the foregoing it is apparent that if the operatinglever were moved, the pawl 30 would successive teeth on the segment 2Q whereby said operating` lever SO would be retained in various positions relative to said segment.

To prevent the air within the air pass vgewa.7 11 from esc ning thrornh the furnace wall around operating sn fts 26, l ein ploy a tube 32 which surrounds Ythe shaft Lio ln use, 'the closuresidV of my furnace are normally closed, in which position the operating levers 80 are in the position 'in which they are shown in Fig. l ofthe drawling with 'the nose of the pawl 3l' being engaged by one ofthe teeth on the toothed face of the segment Q9. in the event it is desired to removethe closure 1S from the ash discharge opening l5 to permit the ashes to be dischargedY therethrough, the extension 3l on the pawl 3l is depressed, which will cause said pawl to swing on its pivot, thereby disengaging the nose thereof from the tooth on the segment .Q9 and permitting said operating lever to be moved in the direction indicated by the feathered arrow in Fig. I, which movement will cause the ciok sure-engaging port-ions 2e of the dogs 2st to move away from said closure and permit same to swing by gravity away from the ash discharge opening.

Upon the removal of the closures 18 from the ash discharge openings l5 in the inanner just described, the ashes within the draft boxes will, of course, drop by gravity through said openings, and will fall onto the lower course of the traveling grate A. The linlis 3 of the grate A are. located coinparatively close to each other in a lateral direction, hence nothing but the smaller particles of ashes would be permitted to pass through said traveling grate until said ashes had been carried to the point indicated by the reference character A in Fig. l', at which point said grate links, due to the fact that the grate A is curved by being passed over the sprocket wheels 6, draw away from each other leaving spaces therebetween, and the ashes will pass through these spaces between said links and fall by gravity to the space under said grate.

lVhen it is desired to remove the portable stolzer from the furnace, the operating lever 30 and the operating shaft 26 are drawn outwardly. thereby disengaging the coupling from the non-circular end 16 of the shaft 16,

in the modification shown in Fig. V, a horizontal closure 18 is shown. In this form of' the invention, a pair of adjustable sealing plates 2l is used. The operation of the mechanism shown in Fig. V is the saine as the operation of the similar mechanism shown in the preferred construction.

I claim:

l. A furnace provided with an endless traveling grate, a draft box surrounded by said grate, said draft box being open at the top for the dischargeof draft through the fuelssupporting portion of the grate and havingan ash discharge opening for the reinoval of ashes therefrom, said draft box being provided with inclined bottom portions' leading tosaid ash discharge opening, a closure, arocltable shaft on which said closure is loosely pivoted, anu members fixed to said rock-able shaft and contacting with said closure whereby same may be moved to a position to close said ash discharge openir furnace provided with an endless traveling grate, a draft box surrounded by said grate, said draft box being open at the top for the discharge of drs ft through the fuelsuppoi-'tiiig portion of the grate and having an ash discharge opening for the removal of ashes therefrom, said draft box being provided with inclined bottom portions leading to said ash discharge opening, a closure, a rochable shaft on which said closure is loosely pivoted, members xed to said lockable shaft and contacting' with said closure whereby saine may be moved to a position to close said ash discharge opening, and means whereby said rochable shaft may be rocked.

A furnace provided with an endless traveling grate, a draft box surrounded by said grate, said draft box being open at the top for the discharge of draft through the fuel-supporting portion of the grate, and having an ash discharge opening for the removal of ashes therefrom, said draft b x being provided with inclined bottom portions leading to said ash discharge opening, a closure, a lockable shaft on which said closure is loosely mounted, dogs fixed to said ioclrable shaft and contacting with said closure whereby saine may be moved to a position to close ash discharge open ing, means extending outside of said furnace whereby said rockable shaft may be rocked, and means including a ratchet and pawl whereby said closure may be locked in a closed position.

4;. A furnace provided with an endless grate, a draft box surrounded by said grate, said draft box being open at the top for the discharge of draft through the fuel-supporting portion of the grate, said draft box being provided with an ash discharge opening whereby the ashes which drop into said draft box may be removed therefrom, a closure for said ash discharge opening, and means comprising an adjustable sealing plate whereby a tight joint between said closure and said draft box is obtained.

5. A furnace provided with an endless grate, a dra-ft box surrounded by said grate, said draft box being open at the top for the discharge of draft through the fuel-supporting portion of the grate and having an ash discharge opening for the removal of ashes therefrom, said draft box also being provided with inclined bottom portions leading to said ash discharge opening, a closure for said ash discharge opening, a sealing plate whereby a tight joint between said closure and said draft box is obtained, said sealing plate being provided With elongated slots, and fastening devices extending through said slots to adjustably secure said sealing plate to said draft box.

6. A furnace provided With an endless grate, a draft box surrounded by said grate, said draft box being open at the top for the discharge of draft through the fuel-supporting portion of the grate, and having an ash discharge opening for the removal of ashes therefrom, said draft box being provided with inclined bottom portions leading to said ash discharge opening, a closure, an adjustable sealing plate whereby a tight joint between said closure and said draftbox is ob tained, a rockable shaft on which said closure is loosely mounted, dogs fixed to said rochable shaft and contacting With said closure whereby same may be moved to a position to close said ash discharge opening, operating means extending outside of said furnace whereby said rockable shaft is rocked, and a ratchet and paWl whereby said closure may be locked in a closed position.

ln testimony that l claim the foregoing i hereunto affix my signature.

WILLIAM M. DUNCAN. 

